放化分析高放废液1AW中的^79Se

应用以溴化硒蒸馏和元素硒沉淀为主要步骤的放化流程，从高放废液１ＡＷ中分离出纯的＾７９Ｓｅ。应用低本底液闪谱仪测量＾７９Ｓｅ，得到了１ＡＷ中＾７９Ｓｅ的含量。     

放化法测量~（79）Se的半衰期

长寿命裂变产物核素￣（７９）Ｓｅ的半衰期还没有被准确地测量过，文献中一直引用１９４９年测定的值：Ｔ＿（１／２）≤６．５×１０￣４ａ。本工作应用放化法测量了￣（７９）Ｓｅ的半衰期。从中子照射的铀靶中分出放化纯的￣（７９）Ｓｅ，并用液闪谱仪测量其活度。利用￣（９０）Ｓｒ、￣（１３７）Ｃｓ作为监测核计算出铀靶的裂变数，然后根据裂变产额得到￣（７９）Ｓｅ核数。得到的￣（７９）Ｓｅ的半衰期为（４．８±０．４×１０￣５ａ。）     

放化法测定^126Sn的半衰期

＾１２６Ｓｎ的半衰期值迄今有准确测量过，文献值 约１０＾５ａ。用放化法从反应堆辐照过的＾２３５Ｕ靶中分离出＾１２６Ｓｎ，用ＨＰＧｅ－Ｓ９０多道分析器测量它的活度；以裂变监测核＾９０Ｓｒ、＾１３７Ｃｓ计算Ｕ靶中发生的裂变数。     

切伦科夫计数法直接测量放射性废水中的^90Sr—^90Y

建立了应用切伦科夫计数技术，不经化学分离直接测量放射废水中＾９０Ｓｒ－＾９０Ｙ－的方法。废水中的存在的大多数干扰核素通过ＨＰＧｅλ谱测量进行校正。对１０种放射性废水中的＾９０Ｓｒ－＾９０Ｙ进行了测量，并与放化分析结果比较，结果表明对于大多数废水样品，这个方法是成功的。     

北京大学6MV串列静电加速器的运行及其应用

北京大学６ＭＶ串列静电加速器上建成４条束流输运线，加速＾１Ｈ，＾１２Ｃ，＾１６Ｏ，＾１９Ｆ，＾３５Ｃｌ，＾７９Ｂｒ等离子，并开展物理实验研究。首次利用Ｄ（＾１２Ｃ，ｐ）＾１３Ｃ核反应建立起高灵敏度的氘分析法；利用共振核反应＾１Ｈ（＾１９Ｆ，αγ）＾１６Ｏ分析材料中氢的深度分布；用重离子背散射分析超导材料ＹＢａ２Ｃｕ３Ｏ７－ｘ；用３５ＭｅＶ＾３５Ｃｌ和４５ＭｅＶ＾７９Ｂｒ的弹性前冲分析不同材料中的轻     

我国市售茶叶中^90Sr,^137Cs和^144Ce的含量

本文报道了１８种国产茶叶中＾９０Ｓｒ、＾１３７Ｃｓ和＾１４４Ｃｅ含量的测定结果，样品灰化用后放射化学联合分析方法测定。结果表明，１９８５年市售茶叶中＾９０Ｓｒ、＾１３７Ｃｓ和＾１４４Ｃｅ的平均含理分别为１７、２．２和０．８Ｂｑ／ｋｇ。     

中能^12C离子反应中^7Be的生成

在最高能量为４７ＭｅＶ／ｕ的＾１２Ｃ离子和Ｍｙｌａｒ、天然铜或＾９３Ｎｂ相互作用中，用离线γ能谱法测量了＾７Ｂｅ的放射性活度，观察到的＾７Ｂｅ起源于入射＾１２Ｃ炮弹的碎裂和靶碎裂两种过程。估计＾７Ｂｅ的产额为１．１×１０＾７Ｂｑ／μＡ·ｈ（单位中的μＡ是粒子μＡ），讨论了利用中能重离子反应生产＾７Ｂｅ以及其它放射性核素的可能性。     

菠菜参考物质中40种元素的中子活化分析

采用仪器中子活化分析和放射化学中子活化分析测定了菠菜参数物质（ＮＩＳＴ－１５７０ａ）中的４０种元素。其中纯仪器分析测定了Ａｇ、Ａｌ、Ｂａ、Ｂｒ、Ｃａ、Ｃｅ、Ｃｌ、Ｃｏ、Ｃｒ、Ｃｓ、Ｅｕ、Ｆｅ、Ｈｆ、Ｋ、Ｌａ、Ｍｇ、Ｍｎ、Ｎａ、Ｎｉ、Ｒｂ、Ｒｅ、Ｓｂ、Ｓｃ、Ｓｅ、Ｓｒ、Ｔａ、Ｔｂ、Ｔｈ、Ｖ、Ｚｎ和Ｚｒ等３１种元素；采用三个简单的放射化学流程测定了另外９种元素：通过除去主要干扰核素＾８２Ｂｒ测定了Ｃｄ     

ICPMS法测量~(126)Sn半衰期

应用电感耦合等离子体质谱法（ＩＣＰ－ＭＳ）测量了长寿命裂片产物核素＾１２６Ｓｎ的半衰期。用乙醚从高放废液０．１ｍｏｌ／Ｌ ＨＣｌ－１．０ｍｏｌ／Ｌ ＮＨ４ＳＣＮ介质中无载体分离＾１２６Ｓｎ后,对样品进行处理,准确分样,一份样品直接用ＩＣＰ－ＭＳ仪测定＾１２６Ｓｎ的浓度,推算出分样前溶液中＾１２６Ｓｎ的原子数;另一份样品加一定量的Ｓｎ载体进一步纯化制源,用ＨＰＧｅγ谱仪测量＾１２６Ｓｎ活度,推算推算     

核素核查数据安全认证模式及裂变核素的最低检测限度模拟

概述了国际放射性核素监测系统中对放射性核素数据在测量过程的安全认证的要求,在推导并模拟铀、钍系衰变链中的相应子体和＾７Ｂｅ等核素从取样至测量过程中放射性活度变化规律以它们比值的基础上,建立样品取样测量运动及认证模式,在计算机拟合的基础上给出了＾９７Ｚｒ、＾１３７Ｃｓ、＾１４０Ｂａ等与ＣＴＢＴ监测系统要求相关的裂变产物核素的最低检测限度,     

从高放废液中分离79 Se的流程研究

建立了离子交换法与沉淀法相结合的、从高放废液中分离79Se的放化流程.该流程具有去污效果好的特点,对137Cs,90Sr,90Y,99Tc,154Eu的去污因子大于104,对125Sb,113Sn的去污因子大于103,对237Np为2×102.整个流程的收率约为53%.由该流程分离出的79Se样品能够很好地满足液闪测量和质谱测量的要求.     

放化分析高放废液1AW中的~(78)Se

应用以溴化硒蒸馏和元素硒沉淀为主要步骤的放化流程,从高放废液1AW中分离出纯的~(79)Se。应用低本底液闪谱仪测量~(79)Se,得到了1AW中~(79)Se的含量。     

Absolute determination of 79Se/80Se with AMS

Selenium-79 measurement with accelerator mass spectrometry (AMS) is increasingly being used for the determinations of ⁷⁹Se relevant nuclear data. Furthermore, ⁷⁹Se was deemed to be an ideal tracer nuclide for long-period and non-intrusive biological studies on selenium. An ultra-sensitive AMS measurement method of ⁷⁹Se has been established at the CIAE-AMS system. For further applications of ⁷⁹Se-AMS, reference standards were requested. ⁷⁹Se can be derived from the ⁷⁸Se(n, γ)⁷⁹Se reaction but cannot be accurately quantified by theoretical calculation owing to the small and dubious cross section and other relevant parameters. In this paper, an AMS method has been developed for the absolute determination of the ⁷⁹Se/⁸⁰Se ratio in a ⁷⁹Se sample with relatively high ⁷⁹Se content. The relative standard uncertainty of ⁷⁹Se/⁸⁰Se ratio is 4.7% and a reference standard is thus acquired. The results are favourable for further applications of ⁷⁹Se-AMS.     

Calculation of half-life for ^79Se decay

1 Introduction The 79Se is one of the fission products with long half-life. It is an important nuclide of radioisotope ap-plications and radioactive waste-treatments, and is also used as the fission monitor. The measurement of its half-life is very difficult, because the differences of half-lives in different experiments are very large. Therefore, it is highly important and interesting to calculate its half-life with Log f 1ut systematics. The calculated half-life has also been compared with…     

79Se半衰期计算

介绍了用log ft系统学计算⁷⁹Se半衰期的方法。根据系统学计算和与实验测量数据的比较，推荐了⁷⁹Se的半衰期。给出了⁷⁹Se衰变纲图并计算得到了⁷⁹Se辐射数据。      

Measurement of 79Se by accelerator mass spectrometry using projectile X-ray technique

1IntroductionInacceleratormassspectrometry(AMS)measurementsoflong-livedradioisotopes,stableisobarsarethedominantbackground.FortheradioisotopesofatomicnumberZ520,theisobarsbackgroundcanbeeliminatedbymeansofthedifferentenergylossofisobarinmatterduetotherateofenergylossisafunctionofZ.Butwithincreasingatomicnumber,theenergystragglingincreasesrelativetotheenergylossdifference,sothatisobarseparationbecomesprogressivelylesseffective.Inordertoseparatetheisobarswithhigheratomicnumberstheionenergyhast…     

Determination of 79Se and 135Cs in Spent Nuclear Fuel for Inventory Estimation of High-Level Radioactive Wastes

⁷⁹Se and ¹³⁵Cs are long-lived fission products and are found in high-level radioactive waste (HLW). The estimation of their inventories in HLW is essential for the safety assessment of geological disposal, owing to their mobility in the strata. In this study, the amounts of ⁷⁹Se and ¹³⁵Cs in a spent nuclear fuel solution were measured. About 5 g of irradiated UO₂ fuel discharged from a commercial Japanese pressurized water reactor (PWR) with a burn-up of 44.9 GWd/t was sampled and dissolved with 50mL of 4M nitric acid in a hot cell for 2 h. After Se and Cs were chemically separated, the amounts of ⁷⁹Se and ¹³⁵Cs in the spent nuclear fuel solution were measured by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). The amounts of ⁷⁹Se and 135Cs were 5:2 ± 1:5 and 447 ± 40 g/MTU, respectively. The results presented in this study, which are the first postirradiation experimental data in Japan, showed good agreement with those obtained by the ORIGEN2 code using the data library of JENDL-3.3.     

Nuclear data sheets for A = 79

The 1966 version of Nuclear Data Sheets for A = 79 has been revised on the basis of experimental data received prior to December 1, 1974. Information from approximately 85 papers and communications has been included in the present evaluation.Data on eight A = 79 nuclei are presented. The half-life and decay energy for ⁷⁹Ga have been proposed, but the compilers do not regard the nuclidic assignment as firmly established. The existence of two isomers in ⁷⁹Ge has recently been proposed. The compilers tentatively assign a 42-s activity to the ⁷⁹Ge ground state, and a partial decay scheme is given. The compilers do not regard the assignment of a 19.1-s activity to ⁷⁹Ge as firmly established. The spin of the ⁷⁹As ground state is known from its decay to levels in ⁷⁹Se. Many levels from ⁷⁹Se are known from ⁷⁹As decay, single-nucleon transfer, and a level scheme for ⁷⁸Se(th n,γ) proposed by the compilers. Only an upper limit for the half-life of long-lived ⁷⁹Se has been determined; this nucleus decays directly to the ⁷⁹Br ground state. Levels in stable ⁷⁹Br up to 2 MeV are known from ⁷⁹Kr decay, Coulomb excitation and resonance fluorescence, and (n,n′γ). Most of the information on excited levels in ⁷⁹Kr is regarded by the compilers as tentative, since the ⁷⁹Rb decay scheme is not well established and all reaction studies are unpublished. Only the ground state of ⁷⁹Rb is known, and its spin cannot be determined since the intensity of the decay to the ⁷⁹Kr ground state is not accurately known. The compilers tentatively assign as 8.1-m activity to the ⁷⁹Sr ground state, but no decay scheme has been proposed. The compilers regard the assignment of a 4.4-m activity to ⁷⁹Sr as not firmly established. The only data on excited levels of ⁷⁹Sr are unpublished.     

Measurement of the 77Se(γ, n) cross section and uncertainty evaluation of the 79Se(n, γ) cross section

The ⁷⁷Se (γ, n) cross section was measured for the energy range from 7.6 to 13.8 MeV by using quasi-monochromatic laser-Compton scattering γ-rays. The advanced method to deduce γ-ray strength functions from (γ, n) cross section was developed. By utilizing the method, the γ-ray strength functions of ^{77, 78, 80}Se were deduced so as to reproduce the ^{77, 78, 80}Se (γ, n) cross sections measured in this work and previous systematic measurements. The inverse (n, γ) cross sections for ^{76, 77, 79}Se isotopes were calculated using the statistical model calculation code CCONE with the deduced γ-ray strength functions. The uncertainty of the calculated ⁷⁹Se(n, γ)⁸⁰Se cross section was evaluated by comparing the calculations and the experimental data on ^{76, 77}Se (n, γ) cross sections.     

中国原子能科学研究院的PX-AMS系统及其应用(英文)

加速器质谱(AMS)中的入射离子X射线方法是为解决AMS测量中重核同量异位素而发展的一种方法(PX AMS),在中国原子能科学研究院建立了PX AMS方法之后,利用这套系统开展了79Se,75Se,64Cu等核素的PX AMS方法测量,基于此技术实现了79Se,75Se半衰期的测量和64Cu放射性核束强度及库仑激发截面的测量。